Stair chair

ABSTRACT

The present invention is directed to a stair chair. The stair chair includes a seat assembly mounted to a main frame and configured to pivot about a first pivot axis. A rail assembly having two laterally spaced brackets provided at a lower end of the rail assembly is included. A back wheel is rotatably supported on each bracket for rotation about a common axis of rotation. At least two mounts are provided at a lower end of the main frame, each of which is configured to pivotally connect one of the brackets to the main frame for movement about a second pivot axis. The rail assembly and seat assembly are configured to pivot about their respective pivot axes independent of movement of one another. A first spacing exists between the axis of rotation of the front wheels and the axis of rotation of the back wheels when the rail assembly in a retracted position and a second spacing exists between the axis of rotation of the front wheels and the axis of rotation of the back wheels when the rail assembly in a deployed position.

FIELD OF THE INVENTION

[0001] This invention relates generally to stair chairs and, moreparticularly, to stair chairs including a seat assembly and a railassembly configured so that the seat assembly and the rail assembly canpivot about respective pivot axes independent of movement of oneanother.

BACKGROUND OF THE INVENTION

[0002] For a number of people, climbing stairs is a difficult, if notimpossible, task. When there is no alternative to the stairs for exitinga building, such as in an evacuation situation, or moving between thefloors of a multi-level building, assistance is often required. Severalchairs, typically referred to as stair chairs in the art, have beendeveloped which are configured to move a person in need up or downstairs.

[0003] Conventional stair chairs include a main frame to which a seatassembly and a rail assembly are mounted. The rail assembly includes aroller, endless track, or other suitable mechanism to facilitatemovement of a person down the stairs. The seat and rail assemblies ofthese conventional stair chairs are configured to pivot together betweenretracted and deployed positions. Thus, the standard stair chair has twoorientations, a first in which the seat and rail assemblies are deployedand a second in which the seat and rail assemblies are retracted.Therefore, the rail assembly must be maintained in a deployed position,thereby making it difficult to move a patient in the stair chair over alevel surface or up one or more steps. Further, due to the combinedweight of the stair chair and a passenger, the chair cannot be pulled upstairs on the rails. Thus, two people are needed to lift theconventional stair chair and carry it up the entire flight of stairssince the rail assemblies cannot be retracted when the seat assembly isdeployed.

[0004] While a number of people have benefited from the aid ofconventional stair chairs, these devices can be further improved. Inaddition to the configuration limitation illustrated above, typicalstair chairs tend to have a relatively small wheel base due to the fixedposition of the wheels. Commonly, front wheels are attached near thefront of the chair and back wheels that are attached to the main frame.When the stair chair is in the deployed position, the rail assemblyprojects from the back of the main frame, leaving the main frame locatednear the middle of the stair chair. This relatively small wheel base canresult in an instability of the stair chair when it is sitting on, orbeing moved along, a level surface.

SUMMARY OF THE INVENTION

[0005] This invention is directed to a new and useful stair chairincluding a main frame. A seat assembly is mounted on the main frame andis configured to pivot about a first pivot axis. The seat assemblyincludes a seat and a support frame that are pivotally mounted to themain frame, wherein at least two laterally spaced front wheels arerotatably attached to a lower end of the support frame. A rail assemblyincluding two laterally spaced brackets provided at a lower end of therail assembly is included. Each bracket has a back wheel rotatablysupported thereon for rotation about a common axis of rotation. At leasttwo mounts are provided at a lower end of the main frame, each of themounts is configured to pivotally connect one of the brackets to themain frame for movement about a second pivot axis. The rail assembly isconfigured to pivot about the second pivot axis independent of movementof the seat assembly and the seat assembly is configured to pivot aboutthe first pivot axis independent of movement of the rail assembly. Afirst spacing exists between the axis of rotation of the front wheelsand the axis of rotation of the back wheels when the rail assembly is ina retracted position and a second spacing exists between the axis ofrotation of the front wheels and the axis of rotation of the back wheelswhen the rail assembly is in a deployed position.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] This invention is pointed out with particularity in theaccompanying claims. The above and further features and benefits of thisinvention are better understood by reference to the following detaileddescription, as well as by reference to the following drawings in which:

[0007]FIG. 1 is an elevational perspective view of a stair chairaccording to the present invention;

[0008]FIG. 2 is a side view of the stair chair of FIG. 1 in a fullydeployed position;

[0009]FIG. 3 is a side view of the stair chair of FIG. 1 in a fullyretracted position;

[0010]FIG. 4A is a side view of the stair chair of FIG. 1 with the seatassembly in a deployed position and the rail assembly in a retractedposition;

[0011]FIG. 4B is a side view of the stair chair of FIG. 1 with the seatassembly in a retracted position and the rail assembly in a deployedposition;

[0012]FIG. 5A is a sectioned front view of the top portion of the stairchair of FIG. 1 with the grab handle in the retracted position;

[0013]FIG. 5B is a sectioned front view of the top portion of the stairchair of FIG. 1 with the grab handle in the fully extended position;

[0014]FIG. 6A is a sectioned side view of the handle of the stair chairof FIG. 1 in a rest position;

[0015]FIG. 6B is a sectioned side view of the handle of the stair chairof FIG. 1 released from the use position; and

[0016]FIG. 6C is a sectioned side view of the handle of the stair chairof FIG. 1 locked in a use position;

[0017]FIG. 7 is a sectioned perspective view of the latch assembly ofthe stair chair of FIG. 1;

[0018]FIG. 8A is a sectioned side view of the stair chair of FIG. 1 withthe upper latch mechanism of the latch assembly engaging one railmember;

[0019]FIG. 8B is a sectioned side view of the main frame of FIG. 1 withthe upper latch mechanism of the latch assembly disengaged from the railmember;

[0020]FIG. 9 is a sectioned side view of the upper latch mechanism ofFIGS. 8A-8B illustrating the latch in an unlocking position;

[0021]FIG. 10A is a sectioned side view of one of one rail member of thestair chair of FIG. 1 with the lower latch mechanism of the latchassembly in a first position;

[0022]FIG. 10B is a sectioned side view of one rail member of the stairchair of FIG. 1 with the lower latch mechanism of the latch assembly ina second position;

[0023]FIG. 10C is a sectioned side view of one rail member of the stairchair of FIG. 1 with the lower latch mechanism of the latch assembly ina third position; and

[0024]FIG. 11 is an elevated perspective view of the stair chair of FIG.1 with the grab handle in the fully extended position.

DETAILED DESCRIPTION

[0025] Referring to FIG. 1 there is illustrated a stair chair 10according to the present invention. The stair chair 10 includes a mainframe 11, on which a seat assembly 12 and a rail assembly 13 arepivotally mounted. The stair chair 10 is supported by two front wheels14 and two back wheels 16.

[0026] The main frame 11 includes two laterally spaced uprights 17. Theuprights 17 are tubular members having a generally rectangularcross-section, each of which has an upper end 18 and a lower end 19.Each upright 17 has a front surface 21 (FIG. 2), a back surface 22 (FIG.2), an inner-facing side surface 23 and an outer-facing side surface 24.The uprights are coupled together by a rod 26 that is attached to theinner-facing surfaces 23 of the uprights 17 near their respective lowerends 19 and a fixed handle 27 interconnecting the upper ends 18. A rod28 extends between the uprights 17. The rod 28 has ends 29 that areslidable in tracks 31 in the inner-facing surfaces 23 of each of theuprights 17. While not illustrated, the bottom of each track 31 isinclined so that the respective end 29 of the rod can be locked inposition at the bottom of the tracks 31.

[0027] A bracket 32, which is preferably extruded, is attached to theupper end 18 of each upright 17 by a suitable means, such as welding.Each bracket 32 includes two spaced apart arms 33 and 34 that extendrearward from the stair chair 10, beyond the back surface 22 (FIG. 2) ofthe associated upright 17. As best illustrated in FIGS. 5A and 5B, thebracket 32 also includes a side extension 35 that forms an opening 36.Each end 37 of the handle 27 is received in one of the openings 36 andwelded to one of the side extensions 35.

[0028] Referring to FIG. 5A, the upper end 18 of each upright 17 ishollow and includes an upwardly opening recess 38. Axially aligned bores39 extend through the inner side surface 23 of the upper end 18 of eachupright 17 into the respective recess 38. As illustrated, a T-shapedstop piece 41 is attached near the upper end 18 of the respectiveupright 17. The stop piece 41 includes a head 42 that is positionedadjacent the inner-facing side surface 23 of the respective upright 17.The stop piece 41 also includes a shank 43 that extends from the head 42through the bore 39 and into the associated recess 38. The stop piece 41includes a spring cavity 44 in which is positioned a coil spring 46. Acentral orifice 47 extends through the head 42 and opens into the springcavity 44. A nut 48 surrounds the portion of the shank 43 that extendsinto the recess 38. The nut 48 is attached to the shank 43 in a suitablemanner, such as by a complementary thread arrangement on the shank 43and the nut 48.

[0029] A bit 49 is partially positioned in each stop piece 41 and isslidable therein. Each bit 49 includes an elongate shank 51 having athreaded end 52 and a head 53. The threaded end 52 of each shank 51extends through the central orifice 47 of the respective stop piece 41.The head 53 is slidably received in the spring cavity 44 of theassociated stop piece 41. When the bit 49 is inserted into therespective stop piece 41, the spring 46 is positioned between a bottomof the spring cavity 44 and a shoulder on the head 53. The spring 46urges the head 53 of the respective bit 49 into the associated recess38.

[0030] A flexible connector 54 extends between the uprights 17. End caps56 are positioned on either end of the connector 54. Each end cap 56includes a cavity 57 that has a set of inner threads. The threaded end52 of the shank 51 is received in the cavity 57 of the respective endcap 56 and is attached thereto by a mating of the complementary threadarrangements. When the connector 54 is pulled, the bits 49 are pulledtoward the center of the stair chair 10 so that the respective heads 53are pulled against the urging of the springs 46.

[0031] A U-shaped handle 58 extends between the uprights 17. The handle58 includes two end segments 59 that are separated by a central portion61. Each end segment 59 of the handle 58 is slidably received in one ofthe upper recesses 38 in the uprights 17. A bushing 60 is attached tothe top of each upright 17. The bushing 60 forms an opening throughwhich the respective end segment 59 can slide. The openings of eachbushing 60 are sized and shaped virtually equal to the outer perimeterof the respective end segment 59 so that the handle 58 does not wobblewith respect to the uprights 17. As illustrated in FIGS. 5A and 5B, anumber of bores 62 extend through each of the end segments 59 of thehandle 58. Each bore 62 is equal in diameter, or slightly larger indiameter, to the head 53 of the stop piece 41 attached to the associatedupright 17. Bushings 63 (FIG. 5B) are positioned around the lowerportion of each of the handle end segments 59. The outer perimeter ofeach bushing 63 is approximately equal to the inner perimeter of therecess 38 of the associated upright 17. As with the bushings 60, thebushings 63 are sized and shaped to prevent the handle 58 from wobblingwith respect to the uprights 17.

[0032] Referring now to FIGS. 6A-6C, a locking element 64 is securedbetween the arms 33 and 34 (FIG. 1) of each bracket 32 by a suitablefastener, such as a bolt. Each fastener forms a pivot axle 66 for itsassociated locking element 64. Each locking element 64 is configured topivot about its respective pivot axle 66 between a first position (FIG.6A and 6C) and a second position (FIGS. 6B). Each locking element 64 iscontinuously urged toward its first position by a biasing spring 67,which is preferably a torsion spring. Each locking element 64 includesan upper tab end 68 that extends upward beyond the top of the associatedbracket 32 and a lower latch end 69. When one of the locking elements 64is in its first position, the tab end 68 is biased to a generallyvertical position, as illustrated in FIGS. 6A and 6C. To move thelocking element 64 toward its second position, the tab end 68 is pulleddownward, away from the associated upright 17 against the bias of thespring 67, causing the locking element 64 to pivot about its pivot axle66 to its second position, as illustrated in FIG. 6B.

[0033] A handle 71 is coupled to each of the uprights 17. Each handle 71has a first end 72 and a second end 73. The first end 72 of each handle71 is secured to each bracket 32 between the associated arms 33 and 34by a suitable fastener, such as a bolt. The fastener forms a pivot axle74 about which the respective handle 71 can pivot. Each handle 71 isconfigured to pivot about its respective axle 74 between a rest, orretracted, position parallel to the associated upright 17 (FIG. 6A) anda use, or deployed, position projecting outward from the back of thestair chair 10 (FIGS. 6B and 6C). The top surface 76 of each handle 71includes a notch 77, or another suitable indentation, adjacent the pivotaxle 74.

[0034] Returning to FIG. 1, a bracket 78 is secured to the inner-facingside surface 23 of each of the uprights 17, near the mid-section of theassociated upright 17. Each bracket 78 has an inner-facing surface 79and an outer-facing surface 81. Each bracket 78 has an end 82 that isoriented rearwardly of the back surface 22 of the respective upright 17.A knob 83 projects from the end 82 of each of the brackets 78 on theinner-facing surface 79.

[0035] Secured to the lower end 19 of each upright 17 is a mount 84.Each mount 84 has a generally triangular shape and has arms 86 that areadjacent the inner-facing and outer-facing surfaces 23 and 24 of theirassociated upright 17. Referring to FIG. 2, a first corner 87 of eacharm 86 of the mounts 84 is secured to the respective upright 17 adjacenta lower end thereof. A second corner 88 of each arm 86 of the mounts 84is spaced downwardly from the lower end of the upright 17. A thirdcorner 89 of each arm 86 of the mounts 84 is oriented frontwardly of thefront surface 21 of the upright 17.

[0036] Referring now to FIGS. 1 and 2, the seat assembly 12 includes aU-shaped frame 91 (FIG. 1) that is secured to the inner facing surface79 of the bracket 78 by a suitable fastener. A seat 92 (FIG. 2) issupported by the frame 91. The seat assembly 12 includes a seat back 90(FIG. 11) that is mounted on the uprights 17 and the handle 27. The seat92 and the seat back 90 are omitted from FIG. 1 to provide a more clearillustration of other components of the stair chair 10. Brace members 93extend between mid-length portion of the seat frame 91 and the rod 28which extends between the uprights 17. The brace members 93 arepivotally attached to both the frame 91 and the rod 28, to allow theframe 91 and the seat 92 to pivot about a pivot axis 94 (FIG. 2) withrespect to the uprights 17 between a retracted position (FIGS. 3 and 4B)and a deployed position (FIGS. 1, 2 and 4A).

[0037] The seat assembly 12 also includes a support frame 96. Referringto FIG. 2, the support frame 96 includes two laterally spaced apart andparallel support arms 97 and two laterally spaced apart and parallelsupport rods 98. When the seat assembly 12 is in its deployed position,as illustrated in FIG. 2, the support arms 97 are oriented generallyhorizontally and the support rods 98 are oriented generally vertically.Each of the support arms 97 has a first end 99 that is pivotally mountedto the third, forwardly oriented, corner 89 of the respective mount 84and between the arms 86. A second end 101 of each of the support arms 97terminates in a handle 102. When the seat assembly 12 is in its deployedposition, the handles 102 project out from the front of the stair chair10. The handles 102 are conventional and are slidable with respect tothe associated support arms 97 between a retracted position and anextended position, the handles 102 being illustrated herein only intheir retracted positions. A button 105 is included on a top surface ofeach of the handles 102. When the button 105 is depressed, a lockingmechanism (not shown) within the respective support arm 97 is released,allowing the associated handle to be moved between its retracted andextended positions.

[0038] As illustrated in FIG. 2, each of the support rods 98 has a firstupper end 103 that is pivotally mounted to the frame 91 by aconventional U-shaped bracket secured to the underside of the frame 91.A front wheel 14 is rotatably attached to a second lower end 104 of eachof the support rods 98. The front wheels 14 are rotatable about an axisof rotation 106 on each wheel yoke 107 that can swivel about avertically upright axis. Extending between the support rods 98 above thewheels 14 adjacent the second ends 104 is a foot rest 108 (FIG. 1). Eachsupport arm 97 is pivotally attached to a respective one of the supportrods 98 by a bolt or other suitable fastener 109. As illustrated, theattachment point of each support arm 97 and support rod 98 pair is justrearward of the handles 102. When the seat assembly 12 is in itsretracted position, each support rod 98 is received by a respective oneof the brackets 95 to lock the seat assembly 12 in its retractedposition. When the seat assembly 12 is moved between its retracted anddeployed positions, the support arms 97 and the support rods 98 pivotwith respect to each other about a common pivot axle 111 formed by thefasteners 109. When the seat assembly 12 is moved to its deployedposition, it is locked in its deployed position when the ends 29 of therod 28 seat in the bottom of each track 31.

[0039] Returning to FIG. 1, the rail assembly 13 includes a pair oflaterally spaced rail members 112. Each rail member 112 includes anupper end 113 and a lower end 114. Each of the rail members 112 has afront surface 116 (FIG. 2), a back surface 117 (FIG. 2), an inner facingsurface 118 and an outer facing surface 119. Referring to FIG. 2, abracket 121 is attached to the lower end 114 of each of the rail members112 and supports thereon one of the back wheels 16 of the stair chair10. A brake pedal 120 is attached to each bracket 121 and can be pivotedto lock or unlock the back wheels 16. The back wheels 16 are rotatableabout a common axis of rotation 122. Each bracket 121 is pivotallyconnected to the second, lowermost corner 88 of the associated mount 84between the arms 86 by a fastener 123 and for movement about a pivotaxis 124.

[0040] The rail members 112 are pivotal together about the pivot axis124 between retracted positions (FIGS. 3 and 4A) and deployed positions(FIGS. 1, 2 and 4B). When the rail members 112 are in their retractedpositions, each rail member 112 is adjacent its respective upright 17and the bracket 121 is in a first position with respect to the mount 84(FIG. 4A). When the rail members 112 are in their deployed positions,the upper end 113 of each rail member 112 is inclined away from the rearof its respective upright 17 and the bracket 121 is in a second positionwith respect to the mount 84 (FIG. 4B), as best illustrated in FIG. 2.

[0041] As best illustrated in FIG. 1, parallel transverse slots 125 and126 extend through the mid-section of the inner-facing and outer-facingsurfaces 118 and 119, respectively of each of the rail members 112. Theslots 125 and 126 are identical in size and shape. A transverse slot 127extends through the inner-facing surface 118 of each of the rail members112. Each rail member 112 is coupled to the respective upright 17 by abrace 128. Referring now to FIG. 2, each brace 128 has a first end 129that is pivotally attached to the outer facing surface 81 of the end 82of the bracket 78. A rod 131 (FIG. 1) extends between the second ends130 of the braces 128. As best illustrated in FIG. 7, each end 132 ofthe rod 131 extends through transverse slots 125 and 126 in theassociated rail member 112 and connects to the respective brace 128. Therod ends 132 are appropriately sized so that they can slide within theslots 125 and 126.

[0042] Returning to FIG. 1, the rail members 112 are coupled to oneanother by two rods 133 and 134. The rod 133 is fixed on either end tothe inner facing surfaces 118 of the rail members 112 in a suitablemanner, such as by welding. The rod 134 is positioned below the rod 133and has ends 136 that extend through the slots 127 in the inner facingsurfaces 118 of the rail members 112. Each end 136 of the rod 134 canslide within the associated slot 127 so that the rod 134 is moveablebetween an upward position, closer to the rod 133 and a downwardposition away from the rod 133.

[0043] Referring to FIG. 4B, an endless belt 137 extends over each railmember 112. The belt 137 includes a top surface 138 that is configuredto engage the edges of one or more stairs. The belt 137 also includes abottom surface 139 that is guided to roll transversely along therespective rail member 112 and is configured to advance the belt 137along the rail member 112 as the stair chair 10 is moved down stairs.The belt 137 moves along a track 135 (FIG. 7) in the front surface 116of the rail members 112. The rail members 112 are preferablysufficiently sized so that the belt 137 can engage the edge of at leasttwo stairs at a time. The belts 137 and tracks 135 are similar to thebelts disclosed in U.S. Pat. No. 4,473,234 which issued to Egen on Sep.25, 1984 and is incorporated by reference herein.

[0044] Referring to FIG. 7, a cut-away view of one rail member 112 isillustrated. A latch assembly 141 is coupled to each of the rail members112. Each latch assembly 141 includes a sliding member 142 that isslidably positioned in the respective rail member 112. An upper end 143of each sliding member 142 is attached to one end 136 of the rod 134which extends into the rail member 112 through the slot 127 (FIG. 1). Astep 145 near the middle of the sliding member 142 is coupled to anupper latch mechanism 146 which is attached to the outwardly facingsurface 119 of the associated rail member 112 (FIG. 1). A lower end 144of each sliding member 142 is coupled to a lower latch mechanism 147that is positioned in the interior of the respective rail member 112(FIGS. 10A-10C). Each sliding member 142 is movable within theassociated rail member 112 between an upper position and a lowerposition and is urged toward its lower position by a biasing spring 148(FIGS. 10A-10C). Thus, when the rod 134 is moved toward its upwardposition, the sliding member 142 is moved upward against the force ofthe biasing spring 148. When the rod 134 is released, the sliding member142 is returned to its lower position by the biasing spring 148, thusmoving the rod 134 toward its downward position.

[0045] Referring to FIGS. 8A, 8B and 9, the upper latch assembly 146includes a conventional rotary latch 149. The rotary latch 149 issimilar to the rotary latches disclosed in U.S. Pat. No. 5,439,260,which issued to Weinerman et al. on Aug. 8, 1995. The rotary latch 149has a front surface 151 and a back surface 152 which are spaced apart byan opening 153 (FIG. 7). The rotary latch 149 is attached to therespective rail member 112 so that the back surface 152 is adjacent theouter-facing surface 119 of the associated rail member 112, asillustrated in FIG. 8A. A lever 154 projects from the back surface ofeach rotary latch 149 and extends into the respective rail member 112.Each lever 154 is secured to the respective rotary latch 149 by afastener which forms a pivot axle 156 about which the associated lever154 can pivot. Each lever 154 can pivot about the associated pivot axle156 between a generally horizontal first position (FIG. 8A) and anupwardly inclined second position (FIG. 8B). Each lever 154 includes anarm 157 that extends into the latch housing 149.

[0046] As best illustrated in FIG. 9, a pawl 158 is rotatably mounted ineach rotary latch 149. Each pawl 158 can pivot between a first positionand a second position (illustrated in FIG. 9), and is urged toward itsfirst position by a first arm 150 of a torsion spring 159. Each pawl 158includes a groove 160 that is sized to receive the arm 157 of therespective lever 154.

[0047] A latch member 161 is secured between the front and back surfaces151 and 152 of the rotary latch 149. Each latch member 161 has two arms163 that are spaced apart by a groove 164. Each groove 164 is sized toreceive the knob 83 on the upper end of the respective bracket 78secured to one of the uprights 17. Each latch member 161 can pivotbetween a locking position in which the arms 163 are oriented verticallyupward and the groove 164 is blocked from the opening 153 in the latchhousing 149 and an unlocking position, illustrated in FIG. 9, in whichthe groove 164 is open to the opening 153. The latch member 161 is urgedtoward its unlocking position, which is illustrated in FIG. 9, by the asecond end 155 of the spring 159. The latch member 161 is positioned inthe rotary latch 149 so that the pawl 158 will hold the latch member 161in its locking position against the force of the spring 159 when thepawl 158 is in its first position.

[0048] Returning to FIGS. 8A and 8B, when the sliding member 142 is inits lower position (FIG. 8A), the lever 154 is in its first position,the pawl 158 is in its first position and the latch member 161 is in itslocking position. When the sliding member 142 is in its upper position(FIG. 8B), the step 145 of the sliding member 142 acts on the lever 154,causing the lever 154 to pivot about the pivot axle 156 toward itsinclined second position. When the lever 154 moves toward this position,the arm 157 acts in the groove 160 of the pawl 158 to move the pawl 158toward its second position against the bias of the spring 159. Once thepawl 158 is moved toward its second position, the latch member 161 ismoved toward its unlocking position by the force of the spring 159.

[0049] Referring now to FIGS. 10A-10C, the lower latch mechanism 147 ispreferably contained in the interior of the associated rail member 112.As illustrated, the lower end 144 of the sliding member 142 includes astep 167. A latch 168 is rotatably positioned within each rail member112 beneath the sliding member 142. Each latch 168 is secured to theassociated rail member 112 by a suitable fastener. Each latch 168 isrotatable about a pivot axle 169 formed by the fastener between lockingand unlocking positions and is continuously urged toward its unlockingposition by a torsion spring 171. A tab 172 extends upward from a topsurface 173 of each latch 168. Two spaced apart arms 174 and 176 extendfrom a side surface 163 of the latch 168. The arm 174 is adjacent thetop surface 173 of the latch 168 and is longer than the arm 176, whichextends from the mid-section of the latch 168. The arms 174 and 176 arespaced apart by a groove 177. Each latch 168 is positioned within theassociated rail member 112 so that the groove 177 is adjacent the top ofthe transverse slot 126 in the outer-facing surface 119 of the railmember 112. Each groove 177 is sized to receive an end 132 of the rod131 (FIG. 7) which extends through the slots 125 and 126 from the brace128.

OPERATION

[0050] When the stair chair 10 is not in use, the seat assembly 12 andthe rail assembly 13 can be maintained in their respective retractedpositions, as illustrated in FIG. 3. To seat a person in the stairchair, the seat assembly 12 is rotated about its pivot axis 94 to itsdeployed position, as illustrated in FIG. 4A. As the seat assembly 12pivots, the rod 28 (FIG. 1) slides downward in the tracks 31 until therod ends 29 seat in the bottom of the tracks 31 and the support arms 97and the support rods 98 pivot about the pivot axle 111 (FIG. 2). Thestair chair 10 can now be positioned upright with both the front wheels14 and the rear wheels 16 in contact with the floor or ground surface.Note the stair chair 10 does not include any components that couple therotation of the seat assembly 12 to the rotation of the rail assembly13. Thus, the seat assembly 12 can be rotated about its pivot axis 94 toits deployed position without a corresponding rotation of the railassembly 13 about its pivot axis 124. Similarly, the rail assembly 13can be pivoted about its axis 124 to its deployed position without acorresponding rotation of the seat assembly 12 about its pivot axis 94,as illustrated in FIG. 4B.

[0051] When the stair chair 10 is to be moved along a flat surface, itwill usually be preferable to leave the rail assembly 13 in itsretracted position. As illustrated in FIG. 4A, when the rail assembly 13is in its retracted position, the axis of rotation 122 of the backwheels 16 is spaced a first distance d₁ from the axis of rotation 106 ofthe front wheels 14. However, when the rail assembly 13 is deployed, asillustrated in FIG. 2, the axis of rotation 122 of the back wheels 16 isspaced a second, smaller distance d₂ from the axis of rotation 106 ofthe front wheels 14. Thus, a wheel base of the stair chair 10 is greaterwhen the rail assembly 13 is in its retracted position than when it isin the deployed position. This configuration will increase stabilitywhen the stair chair 10 is being moved along a level surface and therail assembly 13 is retracted.

[0052] When the stair chair 10 is in the FIG. 4A configuration, a usercould rotate the handles 71 from their rest positions to their usepositions to aid in pushing the stair chair 10. To lock one of thehandles 71 in its use position (FIG. 6B), the handle 71 is rotated aboutits pivot axle 74. As the handle 71 is pivoted, the first end 72contacts the latch end 69 of the locking element 64. The first end 72pushes on the latch end 69 to rotate the locking element 64 toward itssecond position about the pivot axle 66. Once the handle 71 nears itsuse position, the first end 72 moves out of contact with the latch end69 of the locking element 64, allowing the locking element 64 to bereturned to its first position by the spring 67. As the locking element64 returns to its first position, the latch end 69 seats in the notch 77in the top surface 76 of the associated handle 71 (FIG. 6C). Once thelatch end 69 is seated in the notch 77, the handle 71 is prevented fromrotating from its use position and is thus locked in its use position.The other handle 71 can be moved to its use position in an identicalmanner. A user can then grasp the handles 71 and push the stair chair 10along the flat surface.

[0053] To return the handles 71 to their rest positions, the tab end 68of each locking element 64 is pulled downward to rotate the lockingelement 64 about the pivot axle 66 toward its second position,disengaging the respective latch end 69 from the notch 77 (FIG. 6B).Each handle 71 is then pivoted downward about its pivot axle 74 towardits rest position. Release of each tab end 68 will allow the respectivelocking element 64 to return to its biased, first position under theurging of the spring 67 (FIG. 6A).

[0054] To use the stair chair 10 to transport a person down one or moresteps, the rail assembly 13 is unlocked from its retracted position androtated to its deployed position (FIG. 4B). To unlock the rail assembly13 from its retracted position, the rod 134 is pulled upward toward therod 133. Referring to FIGS. 7-9, when the rod 134 is pulled upward, thesliding member 142 is pulled toward its upper position. The step 145 ofthe sliding member 142 acts on the lever 154 to push the lever 154 torotate to its inclined position about the pivot axle 156 (FIG. 8B). Asthe lever 154 rotates toward this position, the arm 157 of the lever 154engages the pawl 158 (FIG. 8B) in the latch housing 149 and pushes thepawl 158 toward its second position. When the pawl 158 moves toward itssecond position, the latch member 161 is forced toward its unlockingposition by the spring 159, as illustrated in FIG. 9. Thus, each knob 83(FIG. 8B) can slide out of the respective groove 64 as the rail members112 are pulled away from the uprights 17. Once the knobs 83 have movedout of the groove 164, the rail members 112 can be pulled outward totheir deployed positions.

[0055] As the rail members 112 are pulled outward, the rod ends 132attached to the braces 128 are pulled upward in their respective pair ofslots 125 and 126 (FIG. 10B). When the rail members 112 near their fullydeployed positions, each end 132 of the rod 131 approaches the top ofthe associated slots 125 and 126. Each latch 168 is in its biased,unlocking position at this time. As the rod 131 continues to moveupward, each rod end 132 seats in the groove 164 in the respective latch168 to engage the latch 168 and move it to its locking position againstthe force of the biasing spring 171. The rod 134 can now be released.Once the rod 134 is released, an upward force is no longer acting on thesliding members 142. Thus, the sliding members 142 are returned to theirdownward positions under the force of the respective springs 148. Thestep 167 on the lower end 144 of each sliding member 142 engages the tab172 on the top surface 173 of the associated latch 168 and holds thelatch 168 in the locking position against the urging of the spring 171(FIG. 10A). The rod ends 132 are now locked against the upper surface ofthe slots 125 and 126 by the arm 176 of the respective latch 168, thuslocking the rail members 112 in their deployed positions.

[0056] The rail members 112 now project from the back of the stair chair10. When the rail members 112 are in their deployed positions, the stairchair 10 can be tilted so that the belts 137 can engage the stairs. Thestair chair 10 can be guided down the stairs. As the stair chair 10moves down the stairs, the endless belts 137 will glide continuouslyalong each rail member 112.

[0057] To transport the stair chair 10 down stairs, the handle 58 can bepulled to one of its extended positions to allow for greater control ofthe stair chair 10. When the handle 58 is in its rest position, asillustrated in FIG. 5A, a majority of each handle end segment 59 iscontained within the recess 38 of the respective upright 17. When thestair chair 10 is configured as illustrated, the handle 58 can be lockedin one of two extended positions. However, it should be appreciated thatthe handle 58 could be configured to be locked in any desirable numberof positions.

[0058] Referring to FIGS. 5A and 5B, to lock the handle 58 in one of theextended positions, such as the position illustrated in FIG. 11, theconnector 54 is pulled, causing an outward force to be applied to theend caps 56. As the end caps 56 are pulled outward, the bits 49 arepulled out of the bores 62 of the respective handle end segments 59against the force of the springs 46. The handle 58 can then be pulledupward. As the handle 58 is pulled upward, the connector 54 can bereleased. The bits 49 will then be moved outward by the associatedsprings 46. As the handle 58 is pulled outward, the head 53 of each bit49 will engage one of the bores 62. The bit 49 will then be moved to itsfully extended position by the associated spring 46 to seat in therespective bore 62. Once the bits 49 are seated in the bores 62, thehandle 58 will be locked in position.

[0059] Once the stair chair 10 has been moved down the stairs, thehandle 58 can be returned to its lowermost position and the rail members112 can be returned to their retracted positions. To unlock the handle58 from this extended position, the flexible connector 54 is pulled,causing each bit 49 to be pulled out of engagement with the respectivebore 62 against the force of the its spring 46. Once the bits 49 aredisengaged from the bores 62 in the handle end segments 59, the handle58 can be pushed downward to slide the end segments 59 into the recesses38 of the uprights 17. The connector 54 can be released to allow thesprings 46 to urge the bits 49 back toward their extended positions.Once the handle 58 has been lowered a sufficient distance, the heads 53of the bits 49 will engage one set of the bores 62. As the bits 49 moveinto engagement with the bores 62, the heads 53 will be pushed into thebores 62 by the force of the springs 46.

[0060] Referring to FIGS. 10A-10C, to release the rail members 112 fromtheir deployed positions, the rod 134 is pulled upward, moving eachsliding member 142 toward its upward position (FIG. 10B). When thesliding member 142 is raised, the step 167 is moved out of engagementwith the tab 172 of the latch 168. The latch 168 is now rotated aboutits pivot axle 169 toward its unlocking position by the spring 171. Theends 132 of the rod 131, which are no longer locked in the grooves 177of the latches 168, can slide downward in the slots 125 and 126 when therail members 112 are pushed toward the uprights 17.

[0061] Referring in addition to FIGS. 8A and 8B, since each slidingmember 142 is in its upper position, the step 145 of each sliding member142 is acting on the associated lever 154 to push the lever 154 towardits inclined second position. The pawl 158 is once again moved towardits second position by the arm 157 of the lever 154 and the latch member161 is in its unlocking position. As the rail members 112 are movedtoward their fully retracted positions, each knob 83 seats in the groove164 of the associated latch member 161. As each rail member 112 ispushed toward the respective upright 17, the force of the knob 83 actingon the associated latch member 161 moves the latch member 161 toward itsunlocking position against the force of the spring 159. The rod 134 canthen be released so that the sliding members 142 return to theirdownward positions under the force of the biasing springs 148. When thesliding members 142 move downward, the levers 154 are returned to theirbiased, first positions. As each lever 154 moves toward its firstposition, the respective pawl 158 is returned to its first position bythe spring 159 to lock the associated latch member 161 in its unlockingposition. Each knob 83 is now locked between the arms 163 of the latchmember 161 so that the rail members 112 are locked in their retractedpositions.

[0062] Once the rail members 112 have been returned to their retractedpositions, the stair chair 10 can be moved over a flat surface, orcarried up one or more steps if desired. Of course, it should beappreciated that the stair chair 10 can be moved over a flat surface,such as a landing between flights of stairs, with the rail members 112in their deployed positions. However, certain users may find it easierto control the stair chair when the rail members 112 are retracted. Inaddition, since the wheel base of the stair chair 10 is larger when therail members are in their retracted positions, the stair chair 10 willhave a greater stability when the rail members are not deployed.

[0063] The stair chair 10 could also be carried up stairs once the railmembers 112 are moved to their retracted positions. To carry the stairchair 10 up one or more steps, the handles 71 are move to their useposition, as previously described. A single operator can then carry thestair chair 10 up the steps. Since the rail members 112 can be retractedwhile the stair chair 10 is in use, the rails will not interfere withthis action.

[0064] When use of the stair chair 10 is complete, the seat assembly 12can be rotated back to its retracted position. Each support rod 98 isreceived in its respective bracket 95 to lock the seat assembly 12 inits retracted position. The stair chair 10 is now folded into aconvenient position for storage, as illustrated in FIG. 3.

[0065] It should be appreciated that the foregoing description is forthe purposes of illustration only, and further alternative embodimentsof this invention are possible without departing from the scope of theclaims. Thus, although particular preferred embodiments of the presentinvention have been disclosed in detail for illustrative purposes, itwill be recognized that variations or modifications lie within the scopeof the present invention and do not depart from the spirit of theinvention, as set forth in the foregoing description and drawings, andin the following claims.

What is claimed is:
 1. A stair chair comprising: a main frame; a seatassembly mounted to said main frame and configured to pivot about afirst pivot axis; said seat assembly including a seat and a supportframe pivotally mounted to said main frame wherein at least twolaterally spaced front wheels are rotatably attached to a lower end ofsaid support frame; a rail assembly, at least two laterally spacedbrackets provided at a lower end of said rail assembly, each saidbracket having a back wheel rotatably supported thereon about a commonaxis of rotation; at least two mounts provided at a lower end of saidmain frame, each of said mounts being configured to pivotally connectone of said brackets to said main frame for movement about a secondpivot axis; said rail assembly being configured to pivot about saidsecond pivot axis independent of movement of said seat assembly and saidseat assembly being configured to pivot about said first pivot axisindependent of movement of said rail assembly; and a first spacingbetween an axis of rotation of said front wheels and said axis ofrotation of said back wheels when said rail assembly is in a retractedposition and a second spacing between said axis of rotation of saidfront wheels and said axis of rotation of said back wheels when saidrail assembly in a deployed position.
 2. The stair chair according toclaim 1, wherein said axis of rotation of said back wheels is positionedrearward of said second pivot axis.
 3. The stair chair according toclaim 1, wherein said rail assembly includes first and second laterallyspaced rail members that are mounted to said main frame and areconfigured to pivot in unison about said second pivot axis between saidretracted and deployed positions.
 4. The stair chair according to claim3, wherein said axis of rotation of said back wheels is moveable aboutsaid second pivot axis when said first and second rail members are movedbetween said retracted and deployed positions.
 5. The stair chairaccording to claim 4, wherein said axis of rotation is spaced a firstdistance from a back side of said main frame when said first and secondrail members are in said deployed positions; and said axis of rotationis spaced a second distance greater than said first distance from saidback side of said main frame when said first and second rail members arein said retracted positions.
 6. The stair chair according to claim 3,wherein said main frame includes first and second laterally spaced apartuprights; and said rail assembly includes first and second connectingmembers, an upper end of each of said first and second connectingmembers is bracketed to a respective one of said first and seconduprights and a lower end of each of said first and second connectingmembers is slidably mounted to a respective one of said first and secondrail members.
 7. The stair chair according to claim 6, including firstand second latch assemblies respectively coupled to said first andsecond rail members and configured to lock said first and second railmembers in at least one of a retracted position and a deployed position;and an elongate rod extends between said first and second rail membersand has a first end attached to said first latch assembly and a secondend attached to said second latch assembly.
 8. The stair chair accordingto claim 7, wherein said first and second latch assemblies areconfigured to respectively engage said upper ends of said first andsecond connecting members when said first and second rail members are insaid retracted positions; and said first and second latch assemblies areconfigured to respectively engage said lower ends of said first andsecond connecting members when said first and second rail members are insaid deployed positions.
 9. The stair chair according to claim 8,wherein each of said first and second latch assemblies includes a lowerlatch mechanism positioned at least partially in a respective one ofsaid first and second rail members; and each lower latch mechanismincludes a spring biased latch configured to respectively engage aprojection extending from said lower end of said first and secondconnecting members.
 10. The stair chair according to claim 9 whereineach of said first and second latch assemblies includes an upper latchmechanism positioned at least partially on an outer surface of arespective one of said first and second rail members and configured torespectively engage a projection extending from said upper end of saidfirst and second connecting member.
 11. The stair chair according toclaim 1, wherein said main frame includes a first upright having a firstupper recess and a second upright having a second upper recess; and agenerally U-shaped grab handle extends between said first and seconduprights and has a first end received in said first upper recess and asecond end received in said second upper recess.
 12. The stair chairaccording to claim 11, wherein said first and second ends of said grabhandle are slidably received in said first and second upper recesses andsaid grab handle is movable between lowered and extended positions; afirst bore extends through said first upright into said first upperrecess and a second bore extends through said second upright into saidsecond upper recess; a plurality of openings extend along a length ofeach of said first and second ends of said grab handle, each configuredto move into and out of axial alignment with a respective one of saidfirst and second bores; and a first pin extends through said first boreand into one of said openings in said first end and a second pin extendsthrough said second bore and into one of said openings in said secondend to lock said grab handle in one of said lowered and extendedpositions.
 13. The stair chair according to claim 1, including twospaced apart handles pivotally attached to a back side of said mainframe, each handle being configured to pivot between rest and usepositions.
 14. The stair chair according to claim 13, including springbiased locking elements respectively coupled to each of said handles andconfigured to lock each of said handles in said use position.
 15. Thestair chair according to claim 1, wherein the rail assembly includesfirst and second laterally spaced apart rail members; and endless beltsrespectively extend over each of said first and second rail members,wherein each endless belt includes coextensive mating surfaces that areconfigured to engage at least two stairs.